LanguageTool
Multilingual AI grammar, style, and spell checker with sentence paraphrasing supporting 30+ languages and open-source self-hosting
Product node overview & trust baseline
Operator provenance, privacy baseline and site-wide pricing belong directly to the product node and are inherited across linked task edgesLanguageTool (created by Daniel Naber in 2003 and operated by LanguageTooler GmbH in Potsdam, Germany) is a globally acclaimed open-source and cloud multilingual proofreading suite. Covering over 30 languages including English, German, French, Spanish, and Chinese, it detects subtle grammatical inconsistencies, punctuation flaws, and misused words while integrating neural AI sentence paraphrasing. It operates an exceptionally transparent freemium model: the Basic Free tier allows anonymous text checking up to 2,000 characters per field with 3 daily AI rewrites; Premium unlocks up to 150,000 characters per check, unlimited AI paraphrasing, and custom style guides, available with explicit multi-period pricing: $24.90/month, $49.90/quarter, $69.90/year, and $119.80 for 2 years.
Germany · Open-source project launched in 2003; commercial service active continuously
Provenance baseline: 19/20 · Stemming from a respected 23-year-old open-source legacy with German jurisdiction and transparent privacy principles.
Explicitly details actual invoice amounts: $24.90/month, $49.90/quarter, $69.90/year, and $119.80 for 2 years; Basic tier is permanently free with 2k chars and 3 daily AI rewrites.
Pricing transparency baseline: 35/35 · Cancellation:
Governed by strict German BDSG and EU GDPR; texts are processed in volatile memory and purged immediately post-check without training use
Stripe · Cloudflare
Product-level pricing & rules baseline
Verified plans, billing periods and cancellation terms owned by this product node; task-specific credit costs and free export limits are detailed per capability edge belowLanguageTool Basic and Premium individual multi-period subscription pricing structure · 2026-10-31
Basic grammar check, punctuation check, personal dictionary
In-depth grammar & punctuation, style improvements, AI paraphrasing, style guide
In-depth grammar & punctuation, style improvements, AI paraphrasing, style guide
In-depth grammar & punctuation, style improvements, AI paraphrasing, style guide
4 plan / billing-period records, all listed; — means that period is not recorded.
Explicitly details actual invoice amounts: $24.90/month, $49.90/quarter, $69.90/year, and $119.80 for 2 years; Basic tier is permanently free with 2k chars and 3 daily AI rewrites.
Cancellation, sources & verification record
Cancellation and refund terms unverified
LanguageTool Premium Official Pricing Page ↗ · 2026-10-31 Capture 1 ↗
Archived official pricing sources: LanguageTool Premium Official Pricing Page (2026-10-31) [text snapshot ↗]
Capability map & linked task edges
Whenever a capability passes fixed-fixture testing, an edge is automatically linked between this product node and the task topic for horizontal comparison.
| Linked task edge | Score | Assessment · historical test | Test scope & delivery | Inspect capability / follow edge |
|---|---|---|---|---|
| AI paraphrasing & rewriting | 88/100 | LanguageTool demonstrated exceptional academic precision in AI text paraphrasing: it restructured the complete benchmark anchor within 4.1 seconds, achieving 67.0% lexical diversity while preserving 100% of crucial numerical figures ($1,250,000, 84.2%) and the verification token without hallucination or truncation. Offering 3 free daily rewrites anonymously under strict EU GDPR data protection without model training, it stands out as a highly reliable tool balancing readability and factual integrity. | TXT · Output attached Historical test · 2026-11-02 Account / tier unconfirmed · 80-word academic & business text master (with currency, percentage & verification token, 756 B) · Output attached |
Tested task edges (with scores and native artifacts) are strictly separated from discovered untested capabilities (unscored).
Peer product comparison across shared task edges
Matched by overlapping tested task edges; compare site-wide billing models alongside per-task benchmark scoresFree tier covers basic notepad and 1,200 words per submission; Basic is $79/yr ($6.58/mo, 1.8M credits), Starter is $129/yr ($10.75/mo, 3.6M credits), Pro is $249/yr ($20.75/mo, 9M credits).
- AI paraphrasing & rewriting：LanguageTool 88/100 vs Editpad (iLoveNote) 88/100
Web readability editor is 100% free with no sign-up; Plus features include a 2-week trial without credit card; monthly rates are Individual 5K $25/mo, Individual 10K $30/mo; annual plans explicitly invoice $100/yr ($8.33/mo equiv) and $150/yr ($12.50/mo equiv).
- AI paraphrasing & rewriting：LanguageTool 88/100 vs Hemingway Editor 65/100
Linked capability test: AI paraphrasing & rewriting
2026-11-02 · Native output attached. Findings cover the recorded fixture and conditions; paid specifications may be untested.
Verified native export & same-run screenshot evidence
Open native exported file (TXT · Output attached) ↗
Task quality
Fact retention 100% · Lexical diversity 67% · Semantic similarity 63.3% · Readability score 100/100
Detailed facts & historical record
- Measured fixture results
Fact retention: 100% · Lexical diversity: 67% · Semantic similarity: 63.3% · Readability score: 100/100
- Fixture findings
In the anchor_paraphrase_v1 benchmark, LanguageTool substantively restructured all 5 sentences with 67.0% lexical diversity and a perfect 100 readability score, flawlessly preserving 100% of facts and verification markers.
- Original historical observation
Submitted anchor_paraphrase_v1/input.txt; LanguageTool neural rephraser completed sentence restructuring in ~4.1s with 67.0% lexical diversity and 100% fact retention.
- Suitable uses · historical assessment
Not verified
- Result & output evidence
Delivery capabilities
TXT · Output attached · Check watermark record
Detailed facts & historical record
- Recorded export specifications
TXT · Output attached · Check watermark record
- Historical specification note · not an official maximum
Not verified
- Watermark observation
Not verified
- Batch & API
Not verified
- Recorded free-tier dimensions
Not verified
- Attached file dimensions
Not verified
Speed & reliability
About 4.1s end to end in this run; reliability not retested
Detailed facts & historical record
- Timing observation
Network-observed server wait: 4.1s · End-to-end reference: 4.1s
- Date & fixture
2026-11-02 · anchor_paraphrase_v1 · US-West (California, AS2914)
- Repeated tests & reliability
No standardized repetition count, success rate or variability range is recorded.
Interaction experience
Account requirement unconfirmed
Detailed facts & historical record
- Account requirements
Not verified
- Sign-in methods
Completely anonymous usage supported; optional Google, Apple, and email login
- Manual adjustment
Not verified
- Interaction observations
Not verified
Background & reputation
LanguageTooler GmbH · Long-term reputation not independently verified
Detailed facts & historical record
- Service lifecycle notice
Not verified
- Operator
LanguageTooler GmbH
- Recorded origin
Not verified
- Domain history record
Not verified
- Background & reputation assessment
Not verified
- External reputation record
Not verified
Engineering & privacy
Uploaded for cloud processing；Explicit retention period unconfirmed; inspect policy record
Detailed facts & historical record
- Processing location
Uploaded for cloud processing
- Third-party tracking record
Stripe · Cloudflare
- Engineering & privacy assessment
Not verified
- Retention statement
Explicit retention period unconfirmed; inspect policy record
Task free allowance & pricing disclosure
3 free AI paraphrasing queries per day without login, up to 1,250 characters per query
Not recorded
Site-wide plans belong to the product node (see Product-level pricing baseline ↑).
Expand site-wide plans aligned for AI paraphrasing & rewriting (4 records)
LanguageTool Basic and Premium individual multi-period subscription pricing structure · 2026-10-31
Basic grammar check, punctuation check, personal dictionary
In-depth grammar & punctuation, style improvements, AI paraphrasing, style guide
In-depth grammar & punctuation, style improvements, AI paraphrasing, style guide
In-depth grammar & punctuation, style improvements, AI paraphrasing, style guide
4 plan / billing-period records, all listed; — means that period is not recorded.
Explicitly details actual invoice amounts: $24.90/month, $49.90/quarter, $69.90/year, and $119.80 for 2 years; Basic tier is permanently free with 2k chars and 3 daily AI rewrites.
Cancellation, sources & verification record
Cancellation and refund terms unverified
LanguageTool Premium Official Pricing Page ↗ · 2026-10-31 Capture 1 ↗
Evaluation basis & full scores · Overall 88/100
Overall = honesty & reputation × 30% + capability × 70%. Component maxima follow this report’s rubric. List scores are rounded for display; original precision is retained here.
Scoring version 2.3.1 · Test fixture anchor_paraphrase_v1
Honesty & reputation · 95/100 · 30%
| Criterion | Score | Rationale | Basis |
|---|---|---|---|
| Pricing transparency | 33 / 35 | Explanation unavailable | Evidence A → |
| Interaction restraint | 28 / 30 | Explanation unavailable | Evidence A → |
| Background & reputation | 19 / 20 | Explanation unavailable | Evidence A → |
| Engineering & privacy | 15 / 15 | Explanation unavailable | Evidence A → |
Capability · 85/100 · 70%
| Criterion | Score | Rationale | Basis |
|---|---|---|---|
| Task quality | 51 / 65 | Fact Retention: 100% · Lexical Diversity: 67% · Semantic Similarity: 63.3% · Readability Score: 100/100 | Evidence A → |
| Deliverable specifications | 20 / 20 | Watermarked or blocked free export (0/8) | Evidence A → |
| Processing speed | 14 / 15 | Network-observed server wait: 4.1s (API mode: sync_json_verified; network upload 0.1s / end-to-end 4.1s shown for reference only, never penalized) | Evidence A → |
Legacy scores may include advertised maximum capabilities. Read tested output separately from paid capabilities. Records without matching tiers and scope are not ranked together.
Developer & citation kit · Claim updates, request benchmarks & embed verified badges
Product developers and writers can embed these SVG badges in official websites, GitHub READMEs or documentation, or use the channels below to sync product-wide plans and capabilities.
[](https://realtest.org/tools/languagetool.org/) <a href="https://realtest.org/tools/languagetool.org/"><img src="https://realtest.org/badges/languagetool.org.svg" alt="LanguageTool — RealTest" height="24" /></a> 
[](https://realtest.org/tools/languagetool.org/#feature-ai-paraphraser)